Multipurpose heat transfer unit



Nov. 3, 1936. c. M. ASHLEY I 2,059,839

MULTIPURPQSE HEAT TRANSFER UNIT Filed Nov. 15, 1933 2 Sheets-Sheet 1 Fig '-J Carlyle I77. .flshleg BY ME 65;;

ATTORNEY IN VEN TOR.

Nov. 3, 1936. c, M, ASHLEY 2,059,839

MULTIPURPOSE .HEAT TRANSFER UNIT Filed Nov. 15, 1953- 2 s eet -sheet 2 INVENTOR.

Carlyle nlflshley BY M 024/ ATTORNEY Patented Noi. 3, 1936 MULTIPURPOSE HEAT TRANSFER UNIT Carlyle M. Ashley, Maplewood, N. 1., assignor, by

mesne assignments. to

Carrier Engineering Corporation, Newark, N. 1., a corporation of New Yo'rli Application November 15, 1933, Serial No. 093,142 j '14 Claims. 01. 251-10) This invention relates to improved heat transfer devices and more particularly to devices for producing high degrees of moisture saturation in air passing therethrough.

The principal object of the invention is to provide a single unitary device which may be used for any one of a number of purposes.

Another object of the invention is to provide a device which will saturate to highdegrees air at a relatively low temperature.

Still another object of the invention is to provide a complete refrigerating device including a compressor, a condenser and an evaporator, in which'said condenser and said evaporator are substantially identical units.

Still another object of the invention is to provide a unitary structure which may be used as an evaporative condenser for condensing refrigerant vapors.

In connection with the foregoing object, it is another object of this invention to provide a water economizer adapted to vary the amount of water supplied to the surface of said condenser in response to changes in pressure, or in certain cases to changes in the temperature, of refrigerant vapors in said condenser.

Still another object of the invention is to provide a. heat transfer device and means for uni-= formly wetting the surfaces of said device for the purpose of. increasing the quantity of heat transferred and for simultaneously humidifying air passing through the device. 1

A feature of the invention resides in the provision of a small unitary structure including a large amount of heat transfer surface, a fan and a spray for wetting the heat transfer surface.

Another feature of the invention resides in the novel spray producing device comprising a rotating target and anozzle for directing a metered quantity of water against said rotating-target.

Still another feature of the invention resides in the use of an air filter made of material such as matted bronze, steel, or other metal turnings, held in position by suitable frames, for removing dirt, dust and entrained free moisture from air passing through the filter. 5-

A further feature resides in the use of an air filter which, in addition to, cleaning air, is adapted to collect free moisture and to present this moisture in intimate contact with air passing through the filter for the purpose of increasing the humidity of the air.

Still another feature of the invention resides in the novel construction of the unit whereby the aforementioned filter may be easily and simply removed for the purpose of cleaning'for replacement and in certain cases for completely omitting the filter.

Another feature of the. invention resides in the utilization of means, for example, corrugated plate fins, on the heat transfer tubes for distributing water evenly over the entire transfer surface.

Other objects and features will be more apparent from the following description and accompanying drawings, in which:

Fig. 1 is anelevational view of one form of the unit, the section being taken on the line iof Fig. 2;

Fig. 2 is a plan view of the unit of Fig. 1, the fan and its driving motor being omitted for the purpose of clarity;

Fig. 3 is a sectional elevation of another form of the invention in which the various cooperating parts shown in Fig. 1 are rearranged;

Fig. 4 is a diagrammatic view of an air conditioning systemillustrating the use of two of applicants units in a complete refrigerating device, one as an evaporative condenser and the other as a refrigerant evaporator; and

Fig. 5 is an isometric view of a fragment-of a heat interchange tube provided with corrugated plate fins. 1

With reference to the drawings, similar designations denoting similar parts, Fig. 1 shows one form of the invention as embodied in a casing l0, preferably constructed of sheet metal, and generally rectilinear in configuration. The casing is open atits opposite ends to provide an air inlet II, and an air discharge l2. Mounted within the casing l0, and approximately midway between its ends, is a heat transfer unit, which in practice, may be of any desired type. As shown inFigs. land 2, however, the unit comprises three parallel rows of finned heat transfer tubes I3. Each row of tubes I3 is, in fact, a single continuous tube bent at opposite sides of the casing in such a manner as to cover substantially the entire free area of the casing. The three 45 tubes are joined 'at one of their ends to air inlet header M, to which a fiuid may be supplied through inlet connection a, and at their other ends to a discharge header l5, from which the fluid may be removed by way of discharge con- 50 nection l5a. Baflles l6, at opposite sides of the casing l0, cover the .bent end portions of the tubes l3, and thus confine air passing through casing ill to the heat transmitting portions of the unit. A filter ll, of the general type in which u removed, as,

a mass of metal turnings 32 is matted andconfined within a frame 33, is mounted in the casing, and is held in position against angles l3 by one or more removable rods It. When desired, the filter may be removed either for cleaning, for replacement, or for total omission, by unfastening the bolts 20 which hold rods l9 in place, and, thereafter, slipping the filter I! out through discharge opening l2.

A fan 2| is adapted to rotate in a plane parallel to, and properly spaced from the rows of tubes l3. The fan is mounted upon, and supported by shaft 22 of motor 23, which, in turn, is supported on cross bars 24, of casing ID. A target 25, which, in practice, may be a small metal disc, a piece of carborundum, or any other hard substance, is fastened to, and rotates with, the end of shaft 22. A small water pipe 28 pierces the filter I! at its center point, and terminates in a nozzle 21 directly opposite target 25. As can best be seen from Fig. i, the target 25, the pipe 20, and nozzle 21 all lie on a common center line. Thus, in operation, water supplied to nozzle 21, from any suitable source through pipe 23, forms a tiny stream which strikes against target 25.

The lower end of casing I0 is turned upwardly, as at 29, to form a trough, or catch basin, 30, from which a drain pipe 3| leads to any desired point of wastage. Trough 30 catches water dripping from the ends of the cooling coils.

The filter l'l, hereinbefore referred to, preferably comprises a mass of matted bronze, brass, or other metal turnings, suitably bound and confined within a frame 33. As is apparent, such a device provides a tremendous surface on which water may collect and be held in contact with a stream of air passing therethrough. Such a device may hereinafter be referred to as a "collecting surface". When the air does not require filtering. applicant may substitute layers of relatively coarse screen to serve as a collecting surface.

In order better to illustrate the invention, its operation will be considered in connection with a refrigerating system including, as essential elements, a cooler, a compressor and a condenser. In such a system, heat is absorbed by the evaporation of a refrigerant in the cooler, is then pumped to a higher temperature inthe compressor, and is finally dissipated by the condensation of refrigerant vapors in the condenser. While both evaporators and condensers are substantially similar in function, i. e., both are heat transfer devices, it has heretofore been considered necessaryto utilize two entirely distinct units for these two similar purposes. Applicant has invented a unit (hereinbefore described) which may be used, alternatively, D086.

Considering first the use of applicant's unit ,as an evaporator (Figs. 1 and 4), numeral 34 represents an enclosure and numeral 33 the unit of Fig. 1, which is to be'used for cooling the enclosure. A suitable refrigerant liquid is supplied to the heat transfer tubes l3 through pipe 36 and inlet connection a under the control of an expansion valve 31, andrefrigerant vapor is for. example, by compressor 33 through discharge connection "a. and pipe 33. Fan 2| forces air from the enclosure through the unit, whereupon the heat of the air is absorbed by the evaporation of refrigerant within tubes l3, and, as a result, the temperature of the air is-reduced to any desired degree. suit, water vapor is condensed from the air,

for either pur- As a further re- Excess moisture falls upon filter l1, and tends to collect in the interstices between the metal turnings 32. Therefore, when the cooled air passes through filter il, not only is dust, dirt and entrained free moisture removed, but contact between the air and moisture collected on the filter insures almost complete saturation of the air. Hence, any air discharged from the unit has a relative humidity of almost one hundred per cent, a result particularly difficult of attainment with any type of surface cooler.

Equally good results are obtained when cold water, or brine, is circulated through tubes i3 in place of the refrigerant hereinbefore mentioned.

Fig. 3 illustrates a modification of the invention when in use as an evaporative condenser (designated unit 35a in Fig. 4) at a point outside of enclosure 3|. Hot refrigerant vapor from compressor 38 is supplied to the heat transfer tubes l3 through pipe 40 and inlet connection Ila, while condensed refrigerant is supplied to unit 33 through pipe 38. Air drawn over the surfaces of the tubes by fan 2| could, if desired, be utilized alone to cause condensation. However, much better and more economical results are secured by wetting tubes is and thus causing the evaporation of water to absorb the heat of condensation given up by the refrigerant. For lack of a better term, applicant has chosen to call such an apparatus, i. e., a wetted surface condenser over which air is blown, an evaporative condenser". Whenever the term occurs in this specification and claims, it is to be read in accordance with this definition. To this end, water is supplied to nozzle 21 which directs a tiny stream against the rotating target 25 located on the end of the fan shaft. The stream of water. upon striking the target, is broken into a fine mist, which mist is distributed over the tubes by the blast of air from fan 2|. Further, the rotation of the target tends to spread the water by centrifugal action, thus giving a better and more even distribution over the entire heat transfer surface.- 1

In this particular application, the filter is frequently not required, As was previously explained. it may easily be removed by the loosening of bolts 20, and removal of rods l3. Where the air used for condensing purposes is particularly' dirty, which dirt would tend to collect on tubes l3, thus reducing their heat transfer coeillcient, a filter may be provided. As shown in Fig. 8, the filter and heat transfer unit are so arranged that water directed against the target 25 is first distributed over the filter.- Air passing through the filter is not only cleaned, wise humidified, and by evaporative cooling, its temperature is very materially reduced. Further, the force of the blast of air tends to drive any unused moisture through the the surface of tubes l3, thus wetting them to increase their heat transfer capacity.

In connection with the operation of the device as an evaporative condenser, it is quite apparent that the temperature of air purposes is as variable as the whim of nature. On certain days, for example, the air is cold and dry; on others, hot and moist; ,and on still others, it may be coldand moist; or hot and dry." Therefore, the amount of water which can profitably be used is a function of the air temperature and humidity. In order to economize on the amount of water used. applicant provides a valve ll (of the general type in which the degree of opening of but is likefilter and against forced over tubes I3 by fan 2|.

the valve is determined by the pressure existing on its operating diaphragm) whose operating diaphragm is subjected, through pipe 42, to the pres-' sure existing in the condenser. Thus, if the day is hot, the pressure in the condenser will tend to rise. This pressure is reflected on the operating diaphragm, thus causing an increased opening of valve II to admit more water. On the other hand, if the air temperature is relatively cool, the pressure in the condenser will decrease. Valve 4| will close to decrease the amount of water supplied. If desired, of course, valve II can be made to operate responsive to the temperature existing in the condenser.

The device illustrated in Fig. 3 is suitable for efficient use as an evaporator. The air passing through the wetted filter is preliminarily cooled, by evaporative cooling. The sensible heat of the air is reduced, and less refrigeration is required in the cooling coils. The air passing through the coils is dehumidified and cooled to a desired low temperature.

The operation of the device as a combined heater and humidifier is in many respects similar to its operation as an evaporative condenser. Thus, steam fed to the tubes l3 (of the unit of Fig. l) is condensed andgives up its heat to air The water mist created by the target spray promotes increased heat transfer, humidifies the air, and collecting on the filter, assists both in cleaning and in humidifying. The amount of humidification accomplished may be controlled by valve 4| operating responsive to any type of well known humidostat.

In connection with the particular type of heat transfer surface used, excellent results are obtainedwith almost any type of extended surface. Therefore, for economy, the so-called spirally wound finned tube is preferable. However,v in those cases in which maximum water distribue tlon over the entire surface is desired, applicant has devised a corrugated plate fin 43, mounted on a heat. transfer tube i311, as is shown in Fig: 5. In operation, the corrugations tend to reverse the direction of air flowing thereover, and consequently, to force the water mist over the entire heat transfer surface.

Since certain changes in carrying out the above process and in the constructions set forth, which embody the invention may be made without departing from its scope, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a heat exchange unit, a casing, a heat exchanger and a collecting surface mounted within said casing, a fan for discharging a stream of air over said heat exchanger and collecting surface, a'target carried by said fan, and a nozzle for directing a stream of water against said target whereby the water will be broken into a fine mist, and the mist distributed over said heat exchanger and collecting surface by the stream of air.

2. In a heat exchange unit, a casing, a heat transfer coil and a filter mounted within said casing, a fan for discharging a stream of air through said casing, a rotating target carried by said fan, and a nozzle for directing a stream of water against said target whereby the water will be broken into a fine mist, the mist thrown from over said coil and filter by the stream of air.

the target by centrifugal action and distributed 3. In a. heat exchange unit, a casing, a heat transfer coil and a filter in said casing, a plurality of corrugated plate fins on said coil, a fan for directing a stream of air through said casing, a target carried by said fan, and a nozzle for directing a stream of water against said target whereby mist from the target will be distributed over said coil and filter.

4. In a heat exchange unit, a casing, a heat transfer coil and a filter in said casing, a fan for directing a stream of air through said casing, a target, means for directing a stream of water against said target, whereby said coil and said filter will be netted, and means for varying the quantity of water.

5. In an evaporative condenser, a casing, a heat transfer coil in said casing, a fan for directing a stream of air through said casing, a target,

means for directing a stream of water againsta stream of air through said casing, a target carried by saidfan, a nozzle for directing a stream of water against said target, and means for varying the quantity of water responsive to pressure variations in said vapor supply means.

'7. In an evaporative condenser, a casing, a heat transfer coil in said casing, means for supplying vapor to said coil, a fan for directing a stream of air through said casing, a rotating target carried by said fan, a nozzle for directing astream of water against said target whereby the water will be broken into a fine mist by impact, thrown from said target by centrifugal force, and distributed over said coil by said air stream, and means for varying saidstream of water responsive to temperature changes in said vapor supply means.

8. In a. heat exchange unit, a casing, a heat transfer coil and a filter in said casing, a fan for directing a stream of air through said casing, a target and means for directing a stream of water against said target, whereby said water will be distributed over said coil and said filter.

9. In a heat transfer unit, a casing, a fan for directing astream of air through said casing, a cooling surface for condensing moisture from said air stream, and a filter composed of metallic tumings for collecting said moisture in the interstices between and on said metallic turnings.

10. An apparatus of the character described, 7

comprising a series of coils, means for circulating refrigerant through the coils, a filter positioned adjacent the coils and arranged to receive directly from the coils moisture condensed upon the coils, whereby air circulated in contact with the coils will pass through and leave the device at a reduced temperature and in substantially saturated condition.

11. A combination of apparatus of the character described comprising a fan, heat exchanger coils, a moisture collecting device, a casing within which all said apparatus is located, and means for supplying moisture to the casing whereby said coils and said device will be wetted and air i'orpassingairin' races oi said coil. whereby said refrigerant vapors will be evaporatively condensed. and means for varying thequantity oi liquid responsive to variations in pressure in said vapor supply means.

14. In a condensing unit, a condenser coil, means for supplying refrigerant vapor to said coil, means for passing air in contact with said coil, and means for supplying a liquid to the outer surfaces of said coil, whereby the refrigerant vapor will'be condensed.

CARLYLE M. ASHLEY,

CERTIFICATE OF CQ REECTION Patent No. 2,059,839. 7

a CARLYLEM. ASHLE November 3, 1936.

is hereby certified that error appears in the printed specification of the above num'oered'patent requiring correction as follows:

column. line 18,- before "when" (Seal) second column,

, Henry Van Arsdale -Acting Commissioner of Patents.

Page 2, second insert the comma, word and comma which, line 19, before "at" insert is suitably positioned; page 3,- line 16, claim 4, for "netted" read wetted; and that the sai eh ould'be read with these corrections therein that the same the record of the case "in the Patent Office. a p Signed and sealed this 26th 'day of January, A. 'D'. 1937.

d Letters Patent may conform to i'orpassingairin' races oi said coil. whereby said refrigerant vapors will be evaporatively condensed. and means for varying thequantity oi liquid responsive to variations in pressure in said vapor supply means.

14. In a condensing unit, a condenser coil, means for supplying refrigerant vapor to said coil, means for passing air in contact with said coil, and means for supplying a liquid to the outer surfaces of said coil, whereby the refrigerant vapor will'be condensed.

CARLYLE M. ASHLEY,

CERTIFICATE OF CQ REECTION Patent No. 2,059,839. 7

a CARLYLEM. ASHLE November 3, 1936.

is hereby certified that error appears in the printed specification of the above num'oered'patent requiring correction as follows:

column. line 18,- before "when" (Seal) second column,

, Henry Van Arsdale -Acting Commissioner of Patents.

Page 2, second insert the comma, word and comma which, line 19, before "at" insert is suitably positioned; page 3,- line 16, claim 4, for "netted" read wetted; and that the sai eh ould'be read with these corrections therein that the same the record of the case "in the Patent Office. a p Signed and sealed this 26th 'day of January, A. 'D'. 1937.

d Letters Patent may conform to 

